AMES, Iowa -- Mark Gordon recently held up a small vial containing three
liquids layered one on top of another.

That middle layer, the brownish one, is an ionic liquid, Gordon
explained.

And that kind of liquid could be a solution to the U.S. Air Force's quest
for a next generation rocket fuel that packs a lot of energy but is better
for the environment and easier on the federal checkbook.

Gordon, Iowa State University's Frances M. Craig Distinguished Professor
of Chemistry and director of the Applied Mathematics and Computational
Sciences program for the U.S. Department of Energy's Ames Laboratory, has
been working as part of an Air Force research collaboration for more than a
decade to come up with ideas for a new and better rocket fuel. Spencer
Pruitt and Toni Smith, Iowa State doctoral students in chemistry, are also
working on the project.

Total support for Gordon's rocket fuel work has been more than $1
million: The Air Force Office of Scientific Research has supported Gordon's
work with grants of about $70,000 per year. The U.S. Department of Defense
is also supporting the work with grants of supercomputing time. The defense
department has also provided $250,000 for a computer cluster featuring
high-speed graphical processing units. Gordon's Craig Chair at Iowa State
also provided support for the computer cluster.

Gordon's work has focused on the project's basic, theoretical side. He's
developing and modeling new ideas in chemistry that have potential as a
rocket fuel.

"One thing that people like me do is take normal molecules and arrange
them in more high-energy, less-stable materials," Gordon said. "And then we
have to figure out how to make something like that so it's not explosive. We
want rocket fuels, not explosives."

The early days of the project focused on developing solid hydrogen fuels
augmented with light materials such as boron to boost the fuel's energy
content. While these new materials worked in theory, Gordon said they
weren't always stable enough to work in practice.

The project's current focus is to study ionic liquids as a potential
rocket fuel. Ionic liquids are salts that can melt down to liquids at room
temperatures. They're composed entirely of ions, atoms that carry electrical
charges because they've lost or gained one or more electrons. The positively
and negatively charged atoms and molecules within the ionic liquids can be
changed, creating a range of materials with adjustable properties.

Gordon says he's optimistic that ionic liquids might work as a rocket
fuel.

First, they're not new materials and have already demonstrated a range of
properties. Second, they're generally non-toxic and can be designed to
minimize pollutants. Third, they can be designed to contain very high
energy.

And, Gordon said, there could be potential to build an ionic liquid that
can ignite by chemical reaction rather than an ignition mechanism. That, he
said, would be the "holy grail" of the project because it makes rocket
engines much easier to control.

"We think we can figure this out," Gordon said. "We need to optimize all
the properties we're looking for. But some of those properties are in
opposition to each other -- to optimize one you minimize another -- so the
challenge is to balance all of this."

Quick look

Mark Gordon of Iowa State University and the U.S. Department of Energy's
Ames Laboratory is part of a U.S. Air Force research collaboration looking
for new and better rocket fuels. The researchers have turned their attention
to ionic liquids -- salts that can melt down to liquids at room temperature
-- as a potential fuel.

Quote

"One thing that people like me do is take normal molecules and arrange them
in more high-energy, less-stable materials. And then we have
to figure out how to make something like that so it's not explosive. We want
rocket fuels, not explosives."

Mark Gordon, Iowa State University's Frances M. Craig Distinguished
Professor of Chemistry and director of the Applied Mathematics and
Computational Sciences Program for the U.S. Department of Energy's Ames
Laboratory